Coolant system



1956 J. J. PRENDERGAST 2,729,203

COOL-ANT SYSTEM Filed Dec. 2'7, 1952 I'T ii I CO0LANT a H TANK 7 72 1 1'1| LIT-J II I 70 7/ Inventor: James J. Prenclergast,

by @W His AttOTh e y.

United States Patent COOLANT SYSTEM James J. Prendergast, Erie, Pa.,assignor to General Electric Company, a corporation of New YorkApplication December 27, 1952, Serial No. 328,197 Claims. (Cl. 123-4112This invention relates to coolant systems, and more particularly tocoolant systems for machinery and lubricating oil coolers onlocomotives.

An object of the invention is to provide a coolant system, requiringonly a single circulating pump, for simultaneously cooling lubricatingoil and various items of machinery, under varying conditions ofoperation.

A further object of my invention is to provide a system of the characterdescribed in the preceding paragraph in which a single radiator or setof radiators may be employed for cooling the coolant for all of theitems mentioned.

Another object of my invention is to provide a coolant system for aninternal combustion engine which keeps the engine warm during stand-byperiods and provides for rapid warm-up to full operating temperaturewhen operation of the engine is begun.

Other objects, features and advantages of my invention are pointed out,in part, and will be apparent in part from the subsequent description ofa preferred embodiment of the invention, while the scope of theinvention is defined in the appended claims.

In carrying out my invention in one form, I provide a coolant system forthe lubricating oil, an auxiliary diesel engine and an air compressor ona locomotive. A single pump withdrawscoolant from a storage tank andcirculates it through an oil cooler and through the engine andcompressor. A portion of the coolant discharged from the pump iscirculated through the oil cooler and then through a radiator, afterwhich at least a part of this portion circulates through the engineunder stand-by conditions when the engine is not operating. The radiatoris provided with a fan which operates whenever con ditions in the systemrequire it. When the engine is started, the circulation of coolant fromthe pump is interrupted for a sufiicient time to allow the engine toreach full operating temperature, after which circulation of coolantfrom the pump is resumed to aid in keeping the engine cool duringoperation. i

For a clearer and more complete understanding of my invention referenceshould be had to the accompanying drawing, the single figure of which isa schematic diagram of the coolant system of my invention as used on agas turbine-electric locomotive.

Referring to the drawing, there is shown a coolant system for a gasturbine-electric locomotive which is equipped with a lubricating oilheat exchanger 10, an auxiliary diesel engine 11 and an air compressor12. The coolant system includes a coolant storage tank 13, a centrifugalpump 14 for withdrawing coolant from tank 13 and circulating it throughthe remainder of the system, and a pair of radiators 15 and 16. 7

It is desirable that the water or the coolant in tank 13 be kept warm,and I disclose in my copending application Serial No. 328,196, for aPiping System, filed concurrently herewith, and assigned to the assigneeof the present application, an arrangement by which condensate from asteam system is discharged into the coolant tank as through a pipe orconduit 17 to keep the water in the coolant tank warm. My copendingapplication also shows an arrangement, not shown in the presentapplication, for admitting a small amount of heated water from a steamgenerator on the locomotive to the coolant tank to aid in keeping thecoolant warm. With either or both of these arrangements, it is desirableto have an overflow pipe 18 extending upwardly into the coolant storagetank to provide a predetermined level in the coolant tank by dischargingany excess of coolant through the said pipe; in the aforementionedcopending application, such overflow is returned to the main waterstorage tank. It will be readily understood, of course, that other meansmay be provided for maintaining the level in the coolant tank and forheating this coolant without departing from the present invention.

In the system illustrated, coolant is withdrawn from tank 13 by pump 14and discharged under pressure into a pipe or conduit 19. From conduit19, a portion of the coolant passes through a smaller pipe 20, thencethrough the cooling water jacket of a compressor 12 and is returnedthrough a return pipe 21 back to the coolant storage tank 13.

The remainder of the coolant discharged by pump 14 passes throughlubricating oil heat exchanger 10 in heat exchange relation with thelubricating oil passing therethrough. Heat exchanger 10 may be of anyconventional type, and as shown the lubricating oil enters the heatexchanger through a pipe or conduit 21a and is discharged through a pipe22. In a typical case, the lubricating oil passing through heatexchanger 10 was used to supply lubrication and cooling for the main gasturbine and gears (not shown) on a gas turbine-electric locomotive,although the invention is not limited to such use.

The coolant discharged from heat exchanger 10 passes through a conduit23 and then through radiators 15 and 16 in series, these two radiatorsbeing interconnected by a pipe or conduit 24.

After leaving radiator 16 the coolant passes downwardly through aconduit 25, from which a portion of the coolant passes through a conduit26. The latter conduit is smaller in size than conduit 25 so that only aportion of the coolant from conduit 25 is able to pass through conduit26. The coolant from conduit 26 passes into a discharge conduit or pipe27 by means of which it is returned to the coolant tank 13. It will beunderstood, of course, that conduit 26 may be provided with an orificeif desired in order to restrict the flow therethrough instead of makingit of smaller diameter than pipe 25.

The portion of coolant from pipe 25 which is unable to pass through pipe26 flows through a conduit 28 and into a second lubricating oil heatexchanger or cooler 29 which is for the engine 11 only. This lubricatingoil cooler like cooler 10 may be of conventional construction, and asshown, the lubricating oil is discharged from the cooler through a pipe30 and returned to the engine, the oil inlet to this cooler not beingshown in order to simplify the drawing.

As shown in the drawing schematically by means of dashed lines, thecoolant from conduit 28 passes through cooler 29 into a pipe or conduit31 from which it enters the cooling Water jacket of engine 11. Afterpassing through the engine coolant jacket, and an internal pump 37 thecoolant is discharged from the engine through an outlet chamber 36 andthen through one or two parallel outlet conduits, depending uponoperating conditions. When the engine is not running, the coolant isdischarged from chamber 36 through a pipe 32 and a normally open valve33 into a conduit 34 which returns it to discharge conduit 27 and thenceback to the coolant tank. When engine 11 is operating, the normally openvalve 33 is closed, and then, providing the engine is up to fulloperating temperature, coolant is discharged through a pipe 35 into pipe34. The. coolant. outlet. chamber. 36. on..engi,ne 11.

includes two valves responsive to the temperature of the coolant. One ofthese, valve 38, is normally closed but opens upon the occurrence of apredetermined temperature of the coolant in outlet chamber 36 to admitcoolant to pipe 35. The other valve which is'des'rgnate'd 39'is alsonormally open but closes upon the occurrence of a secondpredetermined'coolant temperature slightly higher than the temperaturewhich causes valve 38 to operate. A suitable arrangement for valves 38and 3'9and chamber 36. is shown schematically in the drawing, but itwill be understood that other equivalent. arrangements may be employed.

If engine 11 serves as a stand-by unit to provide a source of auxiliarypower when needed, and .is to be ready for instant operation, it isdesirable to keep it warm. This will'be accomplished by the presentsystem providing the" coolant flowing through pipe 'is of the propertemperature to impart heat to the engine as. a portion ofthis' coolantflows therethrough, and' as set forth in detail subsequently this is.the case in the present system.

However, even though engine 11 is kept warm in this manner, it is notkept up to operating. temperature. Therefore, when the engine starts itis desired'to have it reach operating temperature as quickly aspossible. This is accomplished by the electrical control andcoolantbypassarrangement illustrated. on the accompanying drawing and describedinthe succeeding paragraph.

A conduit 40'having. a check valve 41. therein connects the, conduit 32and the junctionof'conduits 28 and'31' withinoil cooler 29. The checkvalve 41' is arranged so that coolant can flow only from the outletchamber 36. of; the engine back to the coolant inlet conduit 31. Theengine 11 is provided with an electrical control. system energizedfromasuitable source of electric current indicated by lines. 42 and. 43.When a switch 44 is closed, an electrically operated valve 45 isactuatedto admitfuel to the engine, and simultaneously the coil of a solenoid.

46. is. energized to. close the normally open valve.v 331 Then when theengine starts, the internal coolant pump 37 in the. engine, circulatescoolant.out through the. outlet chamber 36, through conduit40and checkvalve 41, and. thence. through lubricating. oil cooler. 29' andconduit31..

back into the engine coolant jacket again. This. flow continues until,the engine has reached a temperature. sutfi'cient to open the valve 38in the outlet chamber. 36- and.

permit coolant to. be discharged through pipe 35.and-back to the coolanttank 13 again. Then, a portion of. the coolant circulates throughtheby-pass. 40 while the balance of the coolant required. for engine 11is; admitted. from conduit 28' and after passing through the engine isdis.- charged through conduit 35.. and back to the coolant tank, thelatter.portionrecirculating continuously. through the lubricatingoilheatexchanger 10 and through the. radiators 15'and16. Ultimately,when. the coolant in. cham;-.

ber 36" reaches the second. predetermined. temperature. mentionedpreviously,.valve 39 closes to stop. circulation: In this manner, theenginelfis-brought up to operating. temperature quickly,

of coolant. through the by-pass.

and thereafter is maintained at operatingtemperature.

It will be readily understood that inthe interval for starting andwarming up engine 11 during, which both: the-normally open valve 33andvalve-38 in the enginecoolant outlet lines are closed, that there is areduced: flow of coolant through oil cooler 1.0 and radiators 15' and16, due to the fact that all the .coolant passingthrough these devicesmust pass also through conduit 26. However, this reduced fiow ismaintained. for only. a short time, which does not'seriouslyalfecttheoperation ofthe system, and normal flow is resumed as soon asvalve 38. opens;. Also, it may be pointedout that the. temporaryreduction in How is not directly proportional tothe amountof restrictionimposed. inthe conduit system, but

is'less'than this, because of anincrease. in. pump pressure. when thevolume of flow tends to. drop off.

A pipe. 47 may. be included for conducting any. air or other vapor whichaccumulates in the top of the casing of pump 14 up to the top of tank 13above the liquid in the tank, from which it may pass out to theatmosphere through pipe 17. Radiators 15 and 16 likewise may be providedwith small air vent pipes 48 and 49.

If the various items ofequipment are arranged on the locomotive or otherrail vehicle or machine in approximately the relativeposition shownschematically on the accompanying drawing, i. e.,.with all of the otheritems of equipment higher than the coolant tank, and" if" a small pipe50 is provided connecting the conduit 24 with the tank,1and. a. small.pipe 50a: is;provided:connecting the lowest pointof the engine coolantjacket with the tank, as shown; the entire system will'b'e selfdraining.

When pump 14 is stopped, and the engine 11 is not operating, all of thecoolant in the system will drain back to the coolant tank. This is verydesirable on a locomotive. for example as it minimizes the possibilityof coolant in the radiators and other portions of the system systemincludes a pair: of 'fans 51 and 51a for blowing air respectivelythrough radiators 15 and 16, motors 52- and 53 connected to and drivingthese fans, three temperature responsive electric switches as describedin detail below, and suitable electrical connections to incoming mains42 and 43;

A first electric switch S4 is operated responsively to the temperatureof lubricating oil in conduit 22; As illustrated schematically, switch54 includes a snap acting movable member 55 which normally is inengagement with a fixed contact 56, but upon the occurrence of apredetermined oil temperature in conduit 22 member 55 moves upwardly toengage contact 57. As shown by way of'illus'tration, the operatingmechanism for switch 54 comprises a bulb located'in conduit 22, the bulb60 containing a fluid which increases in volume with the temperature.The bulb 60is connected by means of a conduit 59 to'a bellows 58 whichoperates member 55 between its two positions with a snap action, suchsnap action being produced by a suitable mechanism which isindicated'schematically at 66.

A second switch 61having a normally open fixed contact 62', a movablemember 63, and anormally closed fixed contact 64 is similarly arrangedto be operated responsively to the temperature of the oil in conduit 22,theopera'ting means for switch 61 comprising a bulb 69 located inconduit 22 and containing a temperature responsive fluid, a tube 68connecting bulb 69 with a bellows67, and a snap acting mechanism fortheswitch illustrated schematically at 65. Preferably switches 54 and 61are set to operate at difierent temperatures. For

example, switch 54 may be set to operate at F.,.

while'switch 61 is set to operate at F. This means that only one of thetwo radiator fans operates in many cases when one fan is sufiicient tomaintain the lubricating oil at a suitable temperature. The exact mannerin which this operation is achieved is discussed in detail.

As shown motors 52.and 53 both are connected to one.

electrical supply conductor 42 by means of a conductor 76. The otherterminal of motor 52 is connected by a conductor 77 to the movablemember 55 of switch 54. The other terminal of motor 53 is connected by aconductor 78 to the movable member 63 of switch 61. The fixed terminal62 of switch 61 is connected to the other electrical supply conductor 43by means of conductors 79 and 80. An additional conductor 81 connectsthe fixed terminal 57 of switch 54 to terminal 62 and thereby to thesupply conductor 43.

Assume now for purposes of explanation of the operation of this systemthat the locomotive on which it is installed is operating normally, i.e. the main gas turbine and other machinery on the locomotive areoperating so that considerable heat is being imparted to the lubricatingoil being circulated through heat exchanger 10, but engine 11 is notrunning so that it is imparting no heat to the coolant circulatingtherethrough. Under these conditions, if the temperature of the oilleaving the heat exchanger through pipe 22 should reach 125 F., switch54 will operate to complete the circuit for the operation of fan 51.This circuit may be traced from conductor 42 to conductor 43 through thefollowing circuit: conductor 76, motor 52, conductor 77, switch 54(movable member 55 being in engagement with contact 57 at this time),conductor 81, conductor 79 and conductor 80. Fan 51 will then cool thecoolant being circulated through the lubricating oil heat exchanger 10,and if this provides sufficient cooling, the system will continue inoperation in this manner. If, however, the single fan 51 does notprovide sufiicient cooling so that the temperature of the oil in pipe 22continues to rise, switch 61 will be operated when the temperature ofthis oil reaches 130 to initiate the operation of fan 51a. The circuitfor this fan may be traced in a similar manner to the other as follows:From main conductor 42 through conductor 76, motor 53, conductor 78,movable member 63 of switch 61, contact 62 of switch 61, conductor 79,and conductor 80 back to the other main conductor 43. Any time that thetemperature of the lubricating oil in the conduit 22 drops again for anyreason, the fans will be stopped in reverse order to that in which theywere started. In this manner the lubricating oil on the locomotive ismaintained automatically at a suitable operating temperature.

Next assume that the main gas turbine is not operating, but thatauxiliary engine 11 is operating. Under these conditions considerableheat will be imparted to the coolant by engine 11, but a relativelysmall amount by the lubricating oil in heat exchanger 10. Under thesecircumstances, if the coolant in tank 13 increases in temperature to apredetermined value such as 135 F., for example, due to the warm coolantbeing discharged into the tank from engine 11, switch 73 will beoperated. The closing of this switch starts the operation of both fansto cool the coolant circulating through the radiators and thence throughthe engine 11. The two fan motors will be energized through a circuitwhich may be traced as follows: For motor 52, from conductor 42 throughconductor 76, through motor 52, conductor 77, switch 54 which now is inits lower position shown in the drawing in which member 55 engagescontact 56, a conductor 82 connecting contact 56 to the left contact 75of switch 74, through switch 74, and through conductor 80 back toconductor 43. The circuit for motor 53 may be traced from conductor 76through motor 53, conductor 78, switch 61 in its lower position,conductor 82, switch 74 and through conductor 80 back to main conductor43.

It is not essential to my invention to have two radiators and a separatefan for each, and a single radiator and fan can be used if desiredwithout departing from the invention, however, I have found that thearrangement de scribed above provides a very good regulation of thecoolant temperature under variable operating conditions. Also, while Ihave shown direct current motors drivingthe fans and connected directlyin the electrical control system, it will be readily understood thatother arrangements may be used, such, for example, as alternatingcurrent motors having their starting switches operated by the directcurrent control system.

It will be apparent from the foregoing that my invention provides acoolant system which maintains the lubricating oil and a stand byinternal combustion engine warm and ready for immediate operation, andat the same time provides for automatically cooling both the oil and theengine during operation. These things are accomplished with a systemwhich embodies a single external circulating pump and a relatively smallamount of piping and electrical equipment.

While I have illustrated and described a preferred embodimcnt of myinvention, it will be understood that modifications thereof may be madeby those skilled in the art. Accordingly, it should be understood that Iintend to cover by the appended claims all such modifications which fallwithin the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A coolant system for an oil cooler and an engine comprising, a tankfor containing a supply of coolant, a pump for withdrawing coolant fromthe said tank and circulating it through the oil cooler and the engine,conduit means connecting said tank, said pump, the cooler and the engineso that coolant discharged by the pump flows through the oil cooler andthat at least a portion of said coolant from the cooler flows throughthe engine with substantially all of the coolant discharged by said pumpbeing returned to said tank for recirculation through the system, aradiator connected in circuit with said conduit means between said pumpand the engine whereby at least a portion of the coolant discharged bysaid pump flows through said radiator, a fan for circulating air throughthe said radiator to cool the coolant passing therethrough, meansresponsive to the temperature of oil leaving the cooler for starting theoperation of said fan, and means responsive to the temperature of thecoolant in said tank for starting the operation of the said fan.

2. A coolant system for a fluid heat exchanger and an engine comprising,a tank for containing a supply of coolant, a pump for withdrawingcoolant from said tank and circulating it through the exchanger and theengine, a radiator for cooling said coolant, conduit means connectingsaid tank, said pump, said radiator, the exchanger and the engine sothat coolant discharged by said pump flows through the heat exchangerand said radiator and that at least a portion of the coolant passingthrough said radiator flows also through said engine, substantially allof the coolant discharged by said pump being returned to said tank forrecirculation, a fan for circulating air through said radiator to coolthe coolant flowing therethrough, means responsive to the temperature offluid leaving the fiuid heat exchanger for starting the operation ofsaid fan, and means responsive to the temperature of the coolant in saidtank for starting the operation of the said fan.

3. A coolant system for an oil cooler and an engine comprising a tankfor containing a supply of coolant, a pump hydraulically connected tosaid tank for withdrawing coolant from said tank and circulating itthrough the oil cooler and the engine, a radiator, a first conduitconnecting said pump and the cooler so that at least a portion of thecoolant discharged by said pump flows through the oil cooler, a secondconduit connecting the cooler and said radiator so that coolantdischarged by said pump and flowing through the oil cooler flows alsothrough said radiator, a third conduit connecting said radiator to theengine whereby at least a portion of the coolant passing through saidradiator flows also through the engine, a fourth conduit connecting theengine to said-tank, substantially all of the coolant discharged by saidpump being returned to said tank for recirculation through the system, afan for circulatingair through saidtradiator to coolthe coolant. passingtherethrough, means responsive to the temperatureof'f'oilTleavingjhecooler for startingthe operationof'saidl through theoil cooler and theen'gine, a radiator, a conduit connecting the coolera-ndsaid radiator for conducting coolant flowing through the cooler intosaid radiator, a second conduit arranged to receive coolant dischargedfromtsaidi radiator, a third conduit connected to said second conduitand providing for restricted flow of coolant from said'second-conduitback to said coolant tank, a fourth conduit connecting saidsecond'conduit to the engine whereby the portion of 'coolant in said secondconduit which isnot returned by said. third conduit to said coolant tankflows into the engine, a fifth conduit for conducting the discharge ofcoolant from the engine back to said tank, a. fan for circulating airthrough said'radiator to. cool the coolant flowing therethrough, meansresponsive to the temperature of oil leaving the cooler for startingtheoperation of said fan, and means'responsive to the temperature of thecoolant in said tank for startingthe operation of 'said fan.

SI A coolant system for an oil cooler and an engine comprising, a tankfor containing a supply of coolant. a pump connectedbetween said tankand said oil cooler for withdrawing coolant fromsaid tank' andcirculating it through the oil cooler and the engine, a pair ofradiators, a conduit connecting the cooler and said radiators forconducting the coolant flowing through the cooler into said radiators,,asecond'conduit arranged to receive the coolant discharged'from saidradiators, a third conduit connectedto said second conduit and providingfor re,- strictedfiow of'coolant from said. second conduit back tosaidJcoolant tank, a fourth conduit connecting said second conduit totheengine whereby the portion of coolant in said second conduit which isnot returned by said third conduit'to said coolant tank flows into theengine, a fifth conduit for conducting the discharge of coolant from theengine baclc't'o saidtank, a pair of fans for circulating airrespectively through said radiators to coolthe coolant flowingtherethrough, means responsive to the temperature of oil leaving thecooler for starting the operation of a first of said fans at apredetermined temperature, means responsive to the temperature of theoilleaving the cooler for starting the operation ofthe secondof'saidfans at a higher temperature than said predeterminedtemperature,and means responsive to the temperature of the coolant in said tank forstarting the operation of both said fans at a third temperature higherthan Both of the previously mentioned temperatures.

6.' A coolant system for am'achine that is normally notrunningcomprisinga source of coolant, connections connected to saidcoolant source including an inlet conduit connected to a coolant inletof the machine and parallel outlet conduits connected to a coolantoutlet of the machine, a normally open valve in the first of said outletconduits whereby coolant from said coolant source normallycirculatesthrough the. machine to said coolant source, a thermally operated valveresponsive to the temperatureof coolant leaving the machine closing thesecond of said outlet conduits whenthe temperature of the coolant isbelow a predetermined minimum, a lay-pass connection for. divertingcoolant from said machine coolant outlet back to said machine coolantinlet, a check valve in said by-pass connection permitting flow ofcoolant therethrough only fromsaid'machine coolant outlet toward thesaid machine coolant inlet, and an internal pump in the machine forcirculating coolant therethrough whereby when the machine. startsoperation and said normally open valve is closed said internal pumpcirculates coolant through said'by-pass until the temperatureof'the.coolantleavingthe machine reaches said predetermined. temperaturewhereupon said thermally operated;- valve.

opens to: allow the resumption of circulation of, coolant to and'fromsaid'coolant source,

7'. A coolant system for a normally idle engine having a coolant inletanda coolant outlet chamber, com.- prising a source of coolant,connections connected to said coolant source including an inlet conduitand parallel outlet conduits. said inlet conduit being connected to thecoolant inlet of the engine and said parallel outlet conduits beingconnected to the coolant outlet chamber of the engine, a pumpconnected'to saidcoolant source for supplying coolant under pressure tothe said inlet conduit, anormally open valve in the first of th'esaidoutlet conduits whereby coolant from said coolant source normallycirculates through the. engine to said coolant source, a thermallyoperatedvalve in the outlet chamber responsive to the temperature ofcoolant leaving the engine normally closing the second of said outletcondu'its,.a bypass conduit connected from between the coolantoutletchamber and'the. normally open valve in said first out-. let conduit tosaid inlet conduit, a check valve in the said by-pass conduit permittingflow of coolant there.-

through only from the said first outlet conduit toward the said inletconduit, and an internal pump in the said engine and. driven therebyfor. circulating. coolant therethrough, whereby when the said enginestartsoperation and'the said normally open valve is closed disconnectingsaid second conduit from said coolant source said internal pumpcirculates coolant through the said b'y-pass conduit until thetemperature of the coolant leaving the engine reaches a predeterminedtemperature whereupon the said' thermally operated valve opens to allowa resumption of circulation of coolant to andfrom said coolantsource.

8. A coolant system foran oil cooler anda normally idle engine having acoolant inlet and a coolant outlet chamber comprising, a tank forcontaining a supply of coolant, a pump connected between said tank' andvthe oil cooler for withdrawing coolant from said tank and circulating itthrough the oil cooler and the engine, a pair of radiators, a firstconduit connecting the oil cooler. and

said radiators for conducting the coolant flowing through the oil coolerinto said radiators, a second conduit arranged to receive the coolantdischarged from said radiators, a third 'condt'iit connected to saidsecond conduitv and providing for restricted flow of'coolant from saidsecond. conduitb'ack to said tank, a fourth conduit connecting saidsecond conduit to the coolant inlet of the. engine whereby the portionof the coolant in said'second' conduit which is not returned by saidthird conduit to said tank fiows into the engine, a pair of paralleloutlet conduits connected to the coolant outlet chamber of the engineand arranged to conduct coolant discharged from the engine back tosaid'tank, a normally open valve in the first of said parallel outletconduits whereby coolant normally circulates through the engine and'back to said tank, a thermally operated valve in the outlet chamberresponsive to the temperature of coolant leaving the engine normallyclosing the second of said parallel outlet conduits, a lay-pass conduitconnected from between the coolant outlet chamber and said normally openvalve in said first parallel outlet conduit to said fourth conduit, acheck valve.

in saidby-pass conduit permitting flow of coolant therethrough only fromsaid first parallel outlet conduit toward said fourth conduit, aninternal pump in the engine. and

driven thereby for circulating coolant whereby when the engine startsoperation and said normally open valve is closed'disconnecting saidfirst parallel conduit from said tank,.said internal pump circulatescoolant through said by-pass.conduit until the temperature. of the.coolanttleaving the. engine reaches a predetermined temperaturewhereupon saidthermally operated'valve opens to allow a resumptionof'circulation of. coolant to and'from said tank, a pair of fans forcirculating air respectively through the said radiators to cool thecoolant flowing therethrough, means responsive to the temperature of oilleaving the cooler for starting the operation of a first one of saidfans at a selected temperature, means responsive to the temperature ofthe oil leaving the cooler for starting the operation of the second ofsaid fans at a higher temperature than the said selected temperature,and the means responsive to the temperature of the coolant in said tankfor starting the operation of both of said fans simultaneously at athird temperature higher than both of the two immediately precedingtemperatures.

9. A coolant system for a machine that is normally not runningcomprising a source of coolant, connections connected to said coolantsource including an inlet conduit connected to a coolant inlet of themachine and parallei outlet conduits connected to a coolant outlet ofthe machine, a normally open valve in the first of said outlet conduitswhereby coolant from said coolant source normally circulates through themachine to said coolant source, a first thermally operated valveresponsive to the temperature of coolant leaving the machine closing thesecond of said outlet conduits when the temperature of the coolant isbelow a predetermined minimum, a bypass connection for diverting coolantfrom said machine coolant outlet back to said machine coolant inlet, acheck valve in said by-pass connection permitting flow of coolanttherethrough only from said machine coolant outlet toward the saidmachine coolant inlet, a second thermally operated valve adapted toclose said first outlet conduit and prevent flow through said by-passconnection when the temperature is above said predetermined minimum, andan internal pump in the machine for circulating coolant therethroughwhereby when the machine starts operation and said normally open valveis closed said internal pump circulates coolant through said by-passuntil the temperature of the coolant leaving the machine exceeds saidpredetermined temperature whereupon said first thermally operated valveopens to allow the resumption of circulation of coolant to and from saidcoolant source, and said second operated valve opens to preventcirculation of coolant through said by-pass connection.

10. A coolant system for an oil cooler and a normally idle engine havinga coolant inlet and a coolant outlet chamber comprising, a tank forcontaining a supply of coolant, a pump connected between said tank andthe oil cooler for withdrawing coolant from said tank and circulating itthrough the oil cooler and the engine, a pair of radiators, a firstconduit connecting the oil cooler and said radiators for conducting thecoolant flowing through the oil cooler into said radiators, a secondconduit arranged to receive the coolant discharged from said radiators,a third conduit connected to said second conduit and providing forrestricted flow of coolant from said second conduit back to said tank, afourth conduit connecting said second conduit to the coolant inlet ofthe engine whereby the portion of the coolant in said second conduitwhich is not returned by the said third conduit to said tank flows intothe engine, a pair of parallel outlet conduits connected to the coolantoutlet chamber of the engine and arranged to conduct coolant dischargedfrom the engine back to said tank, a normally open valve in the first ofsaid parallel outlet conduits whereby coolant normally circulatesthrough the engine and back to said tank, a first thermally operatedvalve in the outlet chamber responsive to the temperature of coolantleaving the engine normally closing the second of said parallel outletconduits, a second thermally operated valve in the outlet chamberadapted to close said first parallel outlet conduit, a by-pass conduitconnected from between the coolant outlet chamber and said normally openvalve in said first parallel outlet conduit to said fourth conduit, 2.check valve in said by-pass conduit permitting flow of coolanttherethrough only from said first parallel outlet conduit toward saidfourth conduit, an internal pump in the engine and driven thereby forcirculating coolant whereby when the engine starts operation and saidnormally open valve is closed disconnecting said first parallel conduitfrom said tank, said internal pump circulates coolant through saidby-pass conduit until the temperature of the coolant leaving the enginereaches a predetermined temperature whereupon said first thermallyoperated valve opens to allow a resumption of circulation of coolant toand from said tank, said second thermally operated valve closing saidfirst parallel outlet conduit to prevent coolant flow in said by-passconduit when the temperature of the coolant leaving the engine reaches apredetermined temperature greater than said first mentionedpredetermined temperature whereupon all of said coolant circulatingthrough the engine flows to and from said tank, a pair of fans forcirculating air respectively through the said radiators to cool thecoolant flowing therethrough, means responsive to the temperature of oilleaving the cooler for starting the operation of a first one of saidfans at a selected temperature, means responsive to the temperature ofthe oil leaving the cooler for starting the operation of the second ofsaid fans at a higher temperature than the said selected temperature,and the means responsive to the temperature of the coolant in said tankfor starting the operation of both of said fans simultaneously at athird temperature higher than both of the two immediately precedingtemperatures.

Vincent Aug. 10, 1926 Du Pont May 26, 1942

